The purpose of this grant is to perform in vitro tests seeking antibody and cell-mediated autoimmunity against gastric antigens in selected patients. The patients to be tested include patients with classic pernicious anemia who are not immunodeficient and patients with the pernicious anemia/immunoglobulin deficiency syndrome. The antibody studies include tests for parietal cell microsomal, intrinsic factor blocking and hemagglutinating antibody. The tests for cell mediated autoimmunity include lymphoproliferative responses and lymphokine production by test leukocytes when incubated with gastric antigen. Paired healthy control subjects and control incubations appropriate for individual tests are being performed. Through collaborative efforts, serum gastric levels will be measured concomitantly on each study subject.